Spray gun



Aug. 25, 1936. H. A. RosELUND' 2,052,362

' SPRAY GUN Filed May 22, 193s `Patented Aug. 25, 1936 Unirse sr Pararyori-l v attacca spaar cnn poration oi Ohio Application May 22, i933,se'riai No. tra-,24o

3 claims. (ci. 29e-sc).

This invention relates to a spray gun adapted to be attached directly toa small receptacle containing material to be sprayed, and to be carriedin the hand while it is used. Compressed air is supplied to the gun by asmall air compressor and is controlled by a trigger which first opensthe air valve and then the liquid valve. A part of the air stream isdirected through the nozzle, while the remainder serves to build up apressure within the receptacle.

A spray gun of this type is adapted to be supported and manipulated byone hand and, in order that it may not be too heavy, it should be made,as far as practicable, from aluminum. Aluminum, however, is too soft tobe advantageously used for both sides of the threaded connection betweenthe top o1 the receptacle and the cap to which the spray nozzle isconnected.

One object of the invention, therefore, is to provide a spray guncomprising a liquid container and a cap therefor, both composed chiey ofaluminum and having a threaded connection that is reinforced by acollar` of zinc, zinc alloy or similar metal which is materially harderthan the aluminum.

Another object of the invention is to provide means for electivelypreventing any solid particles of the spray material from splashing orbeing otherwise carried into the air chamber oi the nozzle and cloggingit. For this purpose, the air chamber ot the nozzle is separated fromthe upperl the line 2-2of Fig. 1;

Fig. 3 is a partial section taken on the line 3-3 of Fig. 1; l

Fig. 4 is a detail View of an air cap which may be used interchangeablywith that shown in Fig. 1.

Fig. 5 is an enlarged section of the air cap and associated' parts.

The spray gun to which the invention relates comprises a barrel 5 formedat its rear end with a hand grip 6 in front of which is a trigger 1pivotally connected to the barriel, as shown at 8. The front end 9 ofthe barrel has an air cap I0 secured thereto by a suitable union Il.Compressed air is supplied by a small air compressor to the barrel 5through a. port I2 and an air valve I3 controls the ow of the compressedair through a bore til to an air chamber l5 in the front end of the gunfrom which a portion of the compressed air is emitted through the cap ldalong with the liquid coating material which is emitted through an 5inner liquid nozzle it. The ow of liquid from the bottom ofthereceptacle through a conduit ii is controlled by a needle valve it whichis associated with the liquid nozzle iii. The operation of the spraygun, therefore, is eiected through the 10 medium of the trigger i which,as it is pulled back toward the grip t, rst engages the head t@ of theair valve iti to open it against the resistance oi its spring 2u, andthen engages the head 2l of the needle valve to open it against the 15resistance of its spring iii.

The rear end of the gun is pivotally connected at tito the receptaclecap 2t, which is formed centrally with an upwardly disposed hollowextension or neck it terminating in a tapered an-n 20 nular seat it. Thebarrel t is formed with a correspondingly tapered portion 2i whichengages the seat it. The underside of the cap 256i isiormed with anannular seat iii which is adapted to receive a plate 2t. The liquidconduit il, which is 25 secured to the barrel t, has a downwardextension iii secured to its lower end by a suitable union di A nut 3iin threaded engagement with the nipple it secures the plate it to itsseat it 4and at the same time secures the tapered enlargement 2i 30 oithe gun barrel to the tapered seat it.

A bore dt connects the air chamber it with the cavity it within the capextension 25 and communicates with the interior of the receptacle itthrough one or more perforations it formed` inthe plate it. en the gunis in oper-ation, therefore, a part oi' the compressed air passes `tromthe chamber iti through the air cap it, while the remainder oi thecompressed air flows throughV the bore 33, cavity 34 and ports 36 andserves to build up a pressure within the receptacle 35. In order thatthe spray material may not pass into the air chamber i5 to clog up4 thenozzle, the cavity 34 is lled with copper wool or equivalent materialwhich constitutes an eilicient lter. n

In spray guns of this type it is'customary for the cap 24 to have e.screw threaded connection with the top *of the receptacle 35. For thesake of lightness, it is desirable to make the gun and the receptaclechiefly of aluminum. This metal, however, is not adapted to be used forboth sides of the threaded connection because of the possibility ofmutilation of the threads due to the softness of the metal. One side ofythis connec- AAccording to the present construction, this ring 31 istted over the top of the receptacle 35 and the edge of the receptacletop is then flattened over the upper edge of the ring to form a smoothseat against which rests the gasket 38 within the rim 39 of the cap 24.In order to prevent the ring- 31 from turning with relation to thereceptacle top, the ring is formed with notches 40 in its upper inneredge, and the receptacle top is formed with lugs which 'lt therein. p

In order that the ilow of air through the cap I0 may be accuratelydetermined with relation to the pressure upon the liquid within thereceptacle 35, the air for atomizing is caused to pass through meteringholes 4l, usually four in number, which may be bored with the utmostaccuracy through an annular flange 4 Ia provided on the liquid nozzle I6short of'its tip portion, which latter is also preferably tapered.

The forward end of the gun barrel is cylindrically bored to form thechamber l5, and the cap I0 has its rear or inner end of cylindrical formof a size to t into the outer end portion of the bore forming saidchamber. The cap ill is provided in its inner end with the customarycavity for receiving the liquid nozzle I6 and the bottom of such cavityis conical to adapt it to have a tapered seat against the outer taperededge of the nozzle flange MU'. It is important in the spray heads ofguns of this character to have the cap member accurately aligned incoaxial relation to the liquid nozzle, and it is found in practice thatsuch centering is effectively accom'- plished by having the rear end ofthe nozzle of cylindrical form and tted into a cylindrical recess of thebarrel and to cause the bottom of the cap cavity to have a tapered seatagainst a conical portion of the liquid nozzle, such, for instance, asthe ilange 4I". By this arrangement, a tightening of the union Il causesa true centering .of the members I0 and I8 when the parts are inassembled operating relation. The importance of this is emphasized lin aspray gun having a rotatably adjustable cap member which may necessitatefrequent loosening of the union I I for cap adjustment purposes.

In certain situations, as for example, in painting a ceiling, with thereceptacle 35 nearly full of paint, it is desirable to adjust not onlythe angle of discharge but also the plane of the fan spray, so that itwill not be necessary to tlpthe receptacle enough to permit the paint toilow through the ports 36. For this reason, it is preferred to construct-the air cap as shown in Fig. 1. In such construction the discharge boreof the cap I0 seats closely on the tapered tip of the liquid nozzle I6and is provided with passage-v ways I2 through which the metered airfrom the holes 4| passes. 'I'he cap I0 is also formed with a laterallyinclined seat 43, to which a tip 44 is secured by a union nut 45. Thusby loosening the nut Il, the cap I0 may be adjusted circumferentially tocause the iiow to be diverted in any direction desired and by looseningthe nut 45 the tip may be adjusted circumferentially to vary the planeof the fan shaped spray emitted from the slit 46 in the tip 44. Astandard air cap Ill, as shown in Fig. 4, may, however, be usedinterchangeably with the cap I0,

By the construction above described I have produced a spray gun'which isinexpensive, yet durable, and which is extremely light and easilymanipulated. The cap seats firmly on the receptacle and the gun barrelis seated rmly on the cap so that there is no leakage of the spraymaterial. The packing within the cap prevents the escape of any spraymaterial into the air chamber and this packing may be easily renewedwhenever necessary.

Although I have shown and described in detail a specific form of theinvention, itis to be understood that this is merely illustrative andmay be modified considerably without departing from the scope of theappended claims.

What is claimed isz- 1- A spray gun comprising a liquid receptacle, acap releasably mounted on said receptacle and having a gasket portionseating on the receptacle end and provided at its central top portionwith a hollow upward extension, said extension being open at its top andprovided with a conical seat and having a seat at its base portion, agun body having a conical portion seating on the conical seat of saidextension and having a liquid supply tube extending down through saidextension and into the receptacle, a plate received by said tube withinthe receptacle and seating at its edge against the seat at the base ofsaid cap extension, said plate having openings between the receptacleand the hollow of said extension, a nut threaded on said tube andbearing against said plate to effeet opposed clamping coaction off thegun body and plate against their respective seats at opposite ends ofthe cap extension, said gun body having an air passage in communicationwith the hollow of said extension.

2. In a spray gun, a barrel body having a chamber in its forward end, aliquid passage and an air passage in communication with the chamlber, aliquid nozzle carried by the body and having a conical tip communicatingwith said liquldpassage and having a conical portion rearwardly of itstip, which conical portion is formed with air passages extendingtherethrough. an air cap for said chamber rotatably mounted on the bodyand having a cavity in its rear into which the liquid nozzle projectsand having an air passageway in communication with the air passages ofsaid conical portion of the nozzle and therethrough with the chamber,said cavity having a tapered portion spaced rearwardly of the tip of thenozzle and seated against the conical portion of the nozzle and having aliquid discharge passage receiving the conical tip of the nozzle, andreleasable means engaged with the body and with the air cap for drawingthe latter` against the conical portion of the nozzle and simultaneouslytherewith drawing the conical tip of the nozzle against the wallsdefining the liquid passage of the air cap. I

3. A spray gun in accordance with claim 2 wherein the air cap isprovided with an angular tip portion having a common dischargepassageway communicating with the respective air and liquid dischargepassages of the air cap, said common discharge passageway dischargingangularly with respect to the air and liquid discharge passages of theair cap.

HAROLD A. ROSELUND.

